Do Neutrinos Have Evil Twins of Their Own? Section 2: The Weak Left-Hander

(This is the second part of a series about Majorana fermions, neutrinos, and one of the most bizarre unanswered topics in physics. First, read Part 1.)

For those of you who are left-handed and believe that the world wasn’t made with you in mind, what I’m about to say could offer some tiny solace. The universe doesn’t care if you are left-handed or right-handed when it comes to fundamental particles. It has no bearing. Consider all of nature’s forces and their interactions. mass and gravity. Charge and electromagnetism. powerful force and color charge. Are you left-handed? Everything is the same, and no one notices or cares. Are you right-handed? The same is true.

A buzzing electron is continuously switching between its left-handed and right-handed identities, which are the massless twins that unite to form an electron. You don’t care if it’s left-handed or right-handed when it hits you. Its mass and charge are palpable. That’s all.

Yes, with the exception of the feeble nuclear force.

Well, that’s correct—weak nuclear force. The oddball cousin in the military family. The peculiar one. The one that beats a different drum and lives in its own little world. or accordion. or vuvuzela.

Handedness is very important to the weak force. It is so concerned that it only speaks to particles that are left-handed. For particles that are right-handed, it is BLIND. It resembles a germaphobe that will only shake hands with persons who are left-handed.

Wolfgang Pauli, a well-known physicist and general grump, famously said, “I cannot believe God is a weak left-hander.”

He stated that despite being the odd one out, the weak force is crucial to the majority of the cosmos as we know it. One of its superpowers is beta decay, which enables it to enter a neutron, seize one of its quarks, and alter it so that the neutron becomes a proton. Stars glow because of nuclear fusion and fission, which are made possible by this change, among other things.

The tests carried out by Chinese-American scientist Chien-Shiung Wu, also known as Madame Wu, the first lady of physics, who definitively proved that the weak force exclusively acts with left-handed particles, were denigrated by Pauli for years in typical Pauli fashion. Her research revealed that cobalt-60 radioactive decay tends to favor one route over another. Nobody was happy when she first made the revelation because it disrupted the neat picture of the universe that we had been painstakingly creating for decades. But even the old curmudgeon gave in since Madame Wu was quite skilled at gathering proof.

Alright, that’s strange. Alright, universe, whatever. For the most part, this is completely irrelevant. This is due to the fact that all particles, including electrons, alternate between left- and right-handed states continuously. In a way, the weak nuclear force simply “waits” for the left-handed form to appear, which happens extremely quickly, and then grabs it if it wishes to communicate with the electron. The right-handed version is not required.

To further torture this analogy: It would be quite restricted and generally hostile if our germaphobe exclusively shook hands with left-handed people. However, this germaphobe lives in a world full of ambidextrous people.

Therefore, it is irrelevant.

Yes, with the exception of neutrinos.

When it comes to the forces, neutrinos are very choosy. They don’t interact through electromagnetic since they have no electric charge. The strong force is out for them since they lack color charge. They experience gravity because there is no other option if you are a part of this cosmos.

However, the feeble force? Yes, they adore the feeble force. At an event, they are the only type of particle that our left-handed germophobic force will genuinely SEEK OUT. The language they speak is the same. Naturally, they use their left hands to eat the same kinds of food.

At this point, the narrative abruptly stops. as neutrinos are only left-handed.

Really? Every single neutrino that we have ever seen in a physical process is exclusively left-handed. They don’t dart back and forth. They don’t change who they are. Simply put, they are left-handed.

The antineutrinos now? They do exist, however they are exclusively right-handed.

No other particle is like this at all. The identities of any other heavy particle are alternately left-handed and right-handed. However, the neutrino? For neutrinos, only left-handers; for antineutrinos, only right-handers. That’s all. Not a single one of the trillions of neutrinos that pass through your thumb every second is right-handed.

This was long categorized as “weird but fine.” We believed that neutrinos had no mass. Additionally, massless particles like photons are permanently trapped in either left-handed or right-handed mode. We saw both left-handed and right-handed photons in equal amounts, but only left-handed neutrinos and right-handed antineutrinos, which was considered a “problem for another day.”

And then we discovered that neutrinos have mass.

Massless particles are locked into one hand. Massive particles swap back and forth. The neutrino is both massive AND locked.

I don’t know about you, but this sounds like a problem.

IMAGE:

Chien-Shiung Wu, ca. 1950s. Smithsonian Institution / Flickr Commons.